The invention relates to a process for the manufacture of a perforated and preferably textured soft plastic film which is perforated on a sievelike surface under the influence of a pneumatic vacuum in a thermoplastic state on leaving an extruder die.
A process of this kind is disclosed in the EU-A-0059506, where a plastic film is extruded onto a perforating roller and is then perforated with the help of a stream of hot air. The film is removed from this perforating roller via a cooling roller.
A further disclosure is to be found in DE-A-30 16 368, where an already produced film is fed over a perforated cylinder that is subjected to a pneumatic vacuum and hot air is blown at the film from the outside to perforate and emboss it. Before it leaves the cylinder, the film is also cooled with the help of air that is sucked through the film. This means it takes relatively long for film cooling to start with this process as well, which is extremely disadvantageous for the softness of the film.
DE-C-24 09 496 discloses the perforation of an already produced plastic film using a vacuum and hot air. The film is fed over a perforated cylinder inside which is a suction chamber and outside which--opposite the suction chamber--is a hot air nozzle. A particular disadvantage of this process is that the film first has to be heated up to the thermoplastic temperature range before it is perforated. It is especially difficult in this process to produce even film temperature over the whole of the film width.